Audio Research D-90

Stonedeaf,
Thank you for the info.I intend to get the mannual now that I know who to talk to. Your info on the caps is very helpful because the previous owner replaced one cap so i have 8 cans and one little blue cap in this big open area.
I'm a beleiver of sound over appearance but the more I look at it the more it bothers me.I'll either replace the one or I'll replace all.Probably all knowing me.
I replaced all tubes last week. One of the 6l6's was bad and dumb ass me didn't test it first. It burned 2 resistors. So I had to replace those. I want back and tested the tubes I bought (27)I bought spares and 6 out of the 27 were bad and 3 were weak. So if you ever are thinking of buying from a guy with the initials J.B. that plays a fender,BEWARE. These are so called new Mullards Tung Sol and E.H. tubes. But,I did get new tubes in the amp and it is up and running as I type.
I'm running it Byamped with my C.J doing the highs and mids. I think it sounds good but I'd like more back end. My wife says I'm never satisified.Thanks,Bill

Depending on the version of your D90 there is a relay that should probably be removed for reliability issues. It's been a while since I've worked on one and will have to check with the factory to find out if the relay is replaced with a thermistor or not. If anyone is interested in that...Also don't overlook the output tube sockets. Given the age of that amp and the heat the sockets are subjected to, I would go ahead and replace those too. Nice new shiney output tube sockets can actually improve the sonics. If the input tube sockets are not tight..replace those too...G

Hifigeek1,
Thanks for your help.Your right,there are a couple sockets that could be tighter. I got this amp at a good price and I new I'd have work to do on it. My wife likes when I buy fixxer-uppers.She figures if I'm fixxing one I'm not out buying a new one. Leaves her more money to spend on shoes. Thanks to all of you out there for your input. Please keep it coming.I need all the help I can get.I'm one of those that is pretty handy but a master of nothing.Bill

Houseofsound, Does your amp have the white body relay located near the main bank of filter caps? Let me know as I can contact the factory and get a bit of info for you. If your amp is sans relay no worries. G

Relay had crudy contacts 0n mine - burnished contacts,Cramolined and ordered a new one - which I plan to leave taped to my chassis to remind myself that this is something to replace next time I have the covers off ( which i hope is a year or two).
BTW -ARC has made up a replacement cap plus mount for these amps that is pretty cool - they've attached a new and very probably superior cap to a sled that fits right into the holes in the board the old caps mounted to - mechanically this has to be a better way of doing it than the way we did mine -downside is cost - $60 per cap ( X 8 in a 90B).This will probably look more "stock" and also be a lot more rugged in terms of shipping the amp - not important to me - definitely a YMMV situation.
One of the reasons I purchased this particular amp was I knew it's service history - sold new by a friend of mine - owned by a lawyer who used it - but didn't tube roll - sockets where in good shape . Hate replacing tube sockets - so not much interested in units that have been rolled a lot.
Houseforsound - contact me if you'd like my old caps - I will keep one as a sort of reference - but you could have the other 7 if you want them - remember - these are almost 30 year old caps - they're not treasures. Even if tested with a standard cap tester - you really aren't going to know if they're "good". If you know someone with one of the big time ( big bucks) cap analysisers (spl?) (Sencore)- that would be able to tell what kind of shape your (or my) caps are in.Standard cap testers basically will tell you if the caps shot - but not much else.
Also - look into a solder sucker - you're going to need it to get those caps out of the board.